>> In a few cases, I even got 404s, because they didn't support
>> "my" (second) language yet, though they did support English.
> That isn't a legacy problem; it was never correct behaviour.
But such behavior exists. So long as it keeps people from using
an honest Accept header, it makes the Accept header less useful.
On the web, servers are never quite sure when it is safe to
assume conformant behavior from browsers; the problem is more
difficult still for browsers making assumptions about sites.
-jJ